Basing its count on media reports, the Iraq Body Count group estimated that about 37% of these deaths were caused by US-led forces and added that, overall, more than 42,000 Iraqi civilians were injured.

Pentagon spokesman Greg Hicks said the figures released by his department should be regarded as "a kind of a snapshot".

"The defence department doesn't maintain a comprehensive or authoritative count of Iraqi casualties," he told reporters.

The US military reported its 2,000th fatality from the Iraq conflict last week.